fax 01-972-952-9435. AbstractA well in the Shaybah Field was recently worked over by converting the existing 1-km horizontal section to MRC (maximum reservoir contact) well with a total reservoir contact of 18,443 ft. The objectives of the workover program were to improve well productivity by maximizing the reservoir contact as well as to install solid expandable liner as a conduit for downhole flow control system in the future.The original horizontal section was first extended by 6,462 ft, before running expandable liner. Installing a 1,008 ft 5-1/2" expandable liner in near horizontal section encountered considerable difficulties in this well, first with liner stuck, then experiencing stuck expansion cone during the final stage of liner expansion. After these problems were finally overcome, top of expanded liner was successfully pressure tested. Two laterals were sidetracked successfully out of the expandable liner (Lateral -1 = 4,615 ft and Lateral -2 = 7,366 ft) to access additional flow contribution from the reservoir. This paper describes the experiences and lessons learned from hole preparation, running and expanding expandable liner, window exits of expandable liner, and subsequently drilling two 5-1/2" laterals.

TX 75083-3836, U.S.A., fax 01-972-952-9435. Abstract

With the focus on continuous drilling optimization, a collaborative effort was implemented to analyze and assess drilling challenges encountered while drilling extended horizontal wells in the Khurais field in Saudi Arabia. The primary requirement was to enhance the efficiency of conventional downhole motor directional drilling systems in the challenging horizontal reservoir section. The Khurais field is located in a remote area in the central part of Saudi Arabia approximately 200 km from the Saudi capital Riyadh, and 300 km from the Eastern port city of Dammam. The producer wells are drilled in the middle of the field and the water injector wells are drilled close to the field boundaries. An average of 12 rigs worked simultaneously throughout the duration of the project to drill and complete the required increment wells. The horizontal wells are comprised of the producers, trilateral producers and power water injectors. The wells were drilled to an averaged measured depth of 14,000 ft, with an average of 6,500 ft of open hole section across the reservoir. The 6⅛" horizontal hole section is particularly challenging and is drilled with steerable mud motors with the assistance of real time geosteering and logging while drilling (LWD) tools to maintain the horizontal open hole section of the well close to the top of the reservoir within a window of 3 ft. The fracture intervals coupled with high permeability makes the drilling of this section particularly challenging, as mud losses are frequently encountered in this section. The main difficulties to improve the efficiency of the directional drilling process were high drag and differential sticking. To overcome the challenges mentioned above, the drilling team utilized a new sliding technology that interacts with the drilling rig top drive to break the static friction improving the weight transfer to the bit, and thereby increase the rate of penetration (ROP). Through the virtual elimination of differential sticking and reduction of buckling problems, this system smoothly helps to deliver weight down to the bit. Additional benefits of this innovative technology are the prevention of stalling of the mud-motor, steady orientation of tool face and easier steering. The authors will describe the innovative system utilized to improve the ROP during the sliding process by almost 50% and will present real cases supported by field data. They will also illustrate the importance of post-actions review and rig crew training in the achievement of record ROP in sliding mode. Historical cases will be presented and the benefits of the application of this technology in these wells will be explained.

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TX 75083-3836, U.S.A., fax 01-972-952-9435. Abstract